Piston-rammer compression ignition assembly



Dec. 16, 1969 M. RAMSAY 3,483,793

V PISTON-HAMMER COMPRESSION IGNITION ASSEMBLY Filed March 4, 1968 INVENTOR'.

I MARCUS RAMSAY ATTORNEY United States Patent 7 3,483,793 PISTON-RAMMER COMPRESSION IGNITION ASSEMBLY Marcus Ramsay, New Haven, Conn., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Mar. 4, 1968, Ser. No. 710,127 Int. Cl. F41c 11/00 US. Cl. 897 2 Claims ABSTRACT OF THE DISCLOSURE In a power-actuated device utilizing caseless cartridges, a slidable sleeve to engage the caseless cartridge and move the latter to a firing position, and a concentric piston operable to adiabatically ignite a charge of propellant and fire the device.

This invention is directed toward an assembly for use in a power-actuated device, such as a firearm or tool, which assembly includes a slidable sleeve member operable to transfer a charge of propellant from a magazine area to a firing position. The assembly further comprises a piston which is slidably mounted in the sleeve and operable to compress a charge of air and propellant to adiabatically ignite the latter and propel a projectile, working piston, or fastener from the firing position.

It is well known that a mixture of air and propellant vapor can be ignited by adiabatic compression. It is also known that a compacted charge of a suitable propellant, can be ignited by the adiabatic compression of a volume of air confined with the solid propellant. The present invention utilizes this phenomenon to provide a firearm, power-actuated tool, or the like, which is operated with a caseless type of cartridge wherein no casing remains in th receiver or firing chamber after the cartridge has been fired. The device of this invention is especially adapted for use with a cartridge magazine which feeds successive ones of a plurality of caseless cartridges or propellant charges into a position in alignment with a sliding sleeve member from which position the cartridges or propellant charges are transferred by th sleeve member to a firing position. Furthermore, the device of this invention is particularly adapted for use with caseless cartridges having a compacted charge of suitable propellant, which charge is disposed rearwardly of a projectile portion of the cartridge, and which propellant charge does not include any primer material.

It is, therefore, an object of this invention to provide a device for propelling a body by utilization of gases formed from the adiabatic compression ignition of a charge of propellant within the device.

It is a further object of this invention to provide a device of the character described which can be used in conjunction with a magazine containing a number of propellant charges to be fired in the device.

It is a still further object of this invention to provide a device of the character described wherein a propellant charge is moved from a magazine area into a firing position by a slidably reciprocating sleeve.

Other features, objects, and advantages of the invention will become apparent from the following detailed description and accompanying drawings, in which:

3,483,793 Patented Dec. 16, 1969 FIGURE 1 is a side elevation view in section of a firearm embodiment of this invention showing the compression piston in a cocked position, and showing the sleeve in a cartridge pick-up position;

FIGURE 2 is a view similar to FIGURE 1, with the sleeve having moved to a projectile-seating position wherein the projectile is ready for firing; and

FIGURE 3 is a view similar to FIGURE 2 with the compression piston having been moved to its firing position and the projectile having been fired from the gun.

Referring now to FIGURE 1, an embodiment of this invention is shown in th form of a firearm indicated generally by the numeral 2. The firearm includes a barrel 4 having a bore 5, which barrel 4 is threaded to the front end of a receiver of housing 6. It is noted that the barrel 4 includes a rearward tubular portion 8 which extends a substantial distance into the receiver 6 to be housed thereby. The tubular portion 8 of the barrel includes a chamber 10, the wall of which has a plurality of gas sealing grooves 12 therein.

A bolt member 14 is slidably mounted in the receiver 6 for reciprocal movement therein. A tubular sleeve 16 is disposed on the front end of the bolt 14 and connected thereto by means of a threaded collar 18. The sleeve extends into the chamber 10 and is slidably movable between a cartridge pickup position, shown in FIGURE 1, and a cartridge-seating position shown in FIGURE 2. It is noted that the forward end of the sleeve bore has an enlarged counterbore 20, the purpose of which is set forth hereinafter.

An aperture 22 is formed in the bottom wall of the receiver 6 and a slide block 24 is connected to the bolt 14 and extends downwardly through the aperture 22. One or two slide arms 26 (only one of which is shown) are attached at one end to the slide block 24 by means of a pin 28. The other end of the slide arm 26 is connected to a gas operated piston assembly (not shown) which is operative to move the bolt to the rear of the receiver in a well known manner after a cartridge has been fired, thus rendering the device semi-automatic. The gas operated piston assembly can be any one of a number of conventional assemblies which are operated by combustion gases bled off from the barrel through a port after the projectile passes the port. A compressible spring member 30 engages the slide block 24 on one hand, and a shoulder 32 which extends downwardly from the receiver on the other hand. The spring 30 serves to urge the bolt 14 and sleeve 16 toward the cartridge seating position. It is noted that the slide bars 26 may be manually slid to the position shown in FIGURE 1 by grasping a cocking handle 34 which is attached thereto and. extends laterally therefrom so as to be accessible on the exterior of the gun, and pulling the handle 34 toward the rear of the gun. Thus the sleeve 16 may be moved to the cartridge pickup position when the gun is initially loaded.

A piston assembly comprising a head portion 36 is mounted in the receiver 6 for reciprocal movement therein. A piston stem 38 is affixed to the front of the head 36 by means of a threaded collar 40, the stem 38 passing through a passage 42 in the bolt 14 and into the interior of the sleeve 16. The piston stem 38 is slidably movable within the sleeve 16 and includes a plurality of external grooves 44 to provide a gas seal between the piston stem 38 and the sleeve 16. The rear end of the piston head 36 includes a recess 46 in which a compressible spring 48 is disposed. The spring 48 bears against the piston head 36 on one hand, and the receiver wall on the other hand, thus serving to bias the piston assembly to the right in FIGURE 1. A spring guide 50 is joined to the receiver and disposed within the spring.

The bottom surface of the piston head 36 is provided with a notch 52 which engages a finger 54 on a trigger 56 pivotally mounted on a pin 58. The bottom wall of the receiver 6 includes a slot 60 above the finger 54 which permits the latter to engage the piston notch 52. The trigger 56 includes a well 51 in which a compressible spring 53 is disposed, the spring 53 bearing against the receiver wall and serving to bias the trigger 56 in a counter-clockwise direction so that the finger 54 is urged into the slot 60. It is noted that the front surface 62 of the finger 54 is forwardly and downwardly inclined to provide a camming surface whereby the trigger 56 is pivoted in a clockwise direction against the bias of the spring 53 by engagement between the surface 62 and the piston head 36 when the latter is moved rearwardly in the receiver.

The gun further includes a magazine 64 which is mounted in aligned apertures 66, 68 and 70 through the forearm 72, the receiver 6, and the barrel extension 8 respectively. The magazine 64 may be releasably latched to the gun in any conventional manner. The magazine 64 includes a cartridge follower 74 which is upwardly biased by a spring 76. Ones of a plurality of caseless cartridges are fed from the magazine 64 to a position in front of the sleeve 16 when the latter is in the cartridge pickup position shown in FIGURE 1. The caseless cartridges shown include a frontal metallic projectile portion 78, and a rearward propellant portion 80. The propellant portion 80 may be in the form of a compacted pellet which is adhered to the rear face of the projectile portion 78 to form a compound caseless cartridge.

The firearm embodiment of this invention operates in the following manner. The cartridge magazine 64 having a full load of cartridges is mounted on the gun and the bolt 14- is moved to the rear of the receiver 6 manually until the sleeve 16 is in the cartridge pickup position shown in FIGURE 1. It is noted that the manual rearward movement of the bolt 14 also causes the piston assembly to move to the rear of the receiver 6 toward a cocked position since the bolt bears against the front face of the piston head 36. It is also noted that until the sleeve 16 reaches the cartridge pickup position shown in FIGURE 1, the sleeve wall overlies the aperture 70 and prevents a cartridge from being fed into the chamber 10. When the sleeve 16 reaches the cartridge pickup position, a cartridge is fed from the magazine 64 into a position immediately forward of the sleeve 16, while at the same time, the piston head notch 52 is brought into registry with the receiver slot 60, and the trigger finger 54 moves into engagement with the rear wall of the notch 52. In the position shown in FIGURE 1, it is noted that the springs 30 and 48 are both compressed to store energy.

The bolt 14 is then released and is driven forward 'by the spring 30 to the position shown in FIGURE 2. In FIGURE 2 the sleeve 16 is in a cartridge-seating position wherein the propellant portion 80 of the cartridge is disposed within the enlarged counterbore 20 at the front end of the sleeve 16,, and the projectile portion 78 of the cartridge has been driven into gas sealing engagement with a tapered interface defining a seat 82 between the chamber and the barrel bore 5. It is noted that in the cartridge-seating position in FIGURE '2, the sleeve 16 prevents further cartridges from being fed into the chamber 10, and the sleeve 16 is sealed with respect to the wall of the chamber 10 by the grooves 12. It is further 'noted that the piston assembly has been retained in a cocked position by the engagement between the piston head 36 and the trigger finger 54. As shown in FIGURE 2, the front end of the piston stem 38 is rearwardly spaced apart from the front end of the sleeve 16, with the sleeve 16 defining an air filled compression chamber, the rear end of which is sealed by the piston stem 38 and grooves 44, and the front end of which is sealed by the seated projectile. The gun is now ready to be fired.

To fire the gun, the trigger 56 is pulled in a normal manner and the finger 54 is pivoted in a clockwise direction out of engagement with the piston head 36. The spring 48 then drives the piston assembly forward, or to the right in FIGURE 3, and the piston stem 38 is moved forwardly through the sleeve-compression chamber. The air in the sleeve is thus compressed and heated until the propellant portion of the cartridge is adiabatically ignited. This ignition results in the formation of high pressure gases which act upon the projectile portion 78 of the cartridge to propel the projectile through the barrel bore 5. After the projectile has been fired, the components of the system are as shown in FIGURE 3. Any conventional type of gas piston return system which draws compressed ignition gases olf from the barrel may be used to act upon the slide arms 26 to move the bolt 14, sleeve 16, and piston assembly rearwardly to the position shown in FIGURE 1, wherein a second cartridge is fed into the chamber 10, after which the cycle begins again. Of course, since the cartridges are caseless, nothing need be extracted from the receiver after firing.

The device of this invention thus provides a system for the semi-automatic firing of caseless cartridges wherein individual cartridges are automatically fed into a chamber, then moved to a cartridge-seating position, and then fired by adiabatic compression ignition. It is noted that the device need not be limited to a firearm, but can also be in the form of a power operated tool, or the like, wherein semi-automaticity of firing is desirable and advantageous. Were the device a power-actuated tool, the magazine would feed either a propellant charge attached to a fastener, or simply a propellant charge alone into a position to be picked up by the sleeve. In the case where only a propellant charge is fed by the magazine, a working piston would be disposed at the forward end of the chamber adjacent the seat.

Although reference has been made to a particular embodiment of the present invention, various modifications will readily suggest themselves to those skilled in the art and reference should be made to the appended claims to determine the scope of the invention.

What is claimed is:

1. In a power-actuated device operated by adiabatic compression ignition of a primerle'ss charge of propellant, the device being of the type having a housing, a barrel connected to the housing and opening thereinto to define a chamber having a seat, a magazine connected to the housing and operative to feed a caseless propellant charge to a first position rearwardly spaced from the seat, a bolt assembly movably mounted in the housing for reciprocation between a forward position and a rearward position, the bolt assembly including a sleeve extending into the chamber and movable therein, the sleeve defining a compression chamber and further being operative to transfer a charge. of propellant from the first position to a second position adjacent to the seat during movement of the bolt assembly from its rearward position to its forward position, and first spring means connected to the bolt assembly to urge the sleeve toward the seat, the improvement comprising:

(a) a piston slidably mounted in said housing and movable therein between a rearward cocked position and a forward fired position, said piston including a stem portion extending into and movably disposed in said sleeve, and a radially enlarged head portion disposed rearward of said bolt assembly for engagement therewith;

(b) said bolt assembly being operative to engage said piston head to drive said piston from its fired position to its cocked position when said bolt assembly is moved from its forward position to its rearward position;

5 6 (c) second spring means connected to said piston and References Cited glpfirative to bias the latter toward its fired position; UNITED STATES PATENTS (d) sear means releasably engaging said piston when 3,175,494 3/1965 Turner 102%38 the latter is in its cocked position. 3,302,319 2/1967 Rossdet 2. The device of claim 1, further comprising handle 5 3,399,596 9/1968 Joyce et means connected to said bolt assembly and manually operable to move said bolt assembly, and thereby said SAMUEL ENGLE Pnmary Exammer piston, rearwardly through said chamber to pick up and U S C1 X R seat a first charge of propellant and to cock said piston for an initial firing of said device. 10 42 16; 89-156 

